Snare drum instrument



' D. M. PARK 3,328,506 I SNARE DRUM INSTRUMENT Filed June 26, 1964 2 v 60 CYCLE PEAK TO PEAK June 27, 1967 NEGATIVE TRIGGERING SPEAKER 33215 AUDIO AMPLIFIER AMPLIFIER FILTER AMPLIFIER SWITCH 6O CYCLE SOURCE DC I SOURCE GENERATOR DRUM 12 INVERTER AMPLIFIER INTEGRATOR LOW FREQUENCY COMPONENT HIGH FREQUENCY k R Y E% WM w v m m P T N E N o P m C PULSE IN United States Patent 3,328,506 SNARE DRUM INSTRUMENT Donald M. Park, Raleigh, N.C., assignor to The Seeburg Corporation, Chicago, Ill., a corporation of Delaware Filed June 26, 1964, Ser. No. 378,303 Claims. (Cl. 84-1.24)

ABSTRACT OF THE DISCLOSURE An electronic musical circuit simulates a snare drum sound by combining a drum sound source with a snare sound source. The drum circuit employs tuned tank circuits which are responsive to a pulse source. The snare circuit employs the same pulse source with wave shaping devices which provide a keying voltage for keying an AC modulated white noise source productive of the snare sound which is mixed, filtered and amplified with the drum sound to produce the desired snare-drum sound.

The popularity of electric organs has led to the development of musical devices which automatically produce repetitive rhythms lfOI accompaniment with the organ. An explanation of the circuitry employed in one such device known as a side man instrument is given in' my prior Patent 3,105,106 and reference is made to such patent for the background of the present invention. In particular, the side man instrument has given rise to a need for a great variety of electrically produced sounds which sound sources are spoken of as instruments. For example, modern automatic repetitive rhythm devices may include instruments producing sounds such as base drum, tom toms, blocks and cymbals. A particularly difiicult sound to produce however has been the sound of the snare drum.

The general object of the present invention is therefore to produce electrically a new kind of sound effect.

More specifically, the object of the invention is ,to produce a snare drum instrument for use in an automatic repetitive rhythm side man type device.

The above and other objects will appear from the de- 'scription following and the drawings, in which:

FIGURE 1 is a block diagram of a circuit embodying the snare drum instrument of the invention,

FIGURE 2 is a schematic circuit diagram of the snare drum instrument.

Referring to the drawings, a suitable DC source 10 (plus 15 v. DC being used in the circuit illustrated) energizes' an inverter-amplifier circuit 11, a drum circuit 12, and a furthe rcomposite circuit 13 labeled filter amplifier switch. The output of the drum 12 is fed into a voltage (2 volt 60 cycle AC being used in the circuit illustrated). White noise is understood in the art to means a noise of scrambled frequencies such as in a static or in a television set turned to a blank channel and maximum volume. The output of the filteramplifier switch wires 81, 82 and 83.

indicated. Considering the circuitry and first the drum circuit 12 in more detail, the desired drum effect which is fed on wire 25 to audio amplifier 14 is obtained from a combination of a high component 27. High frequency component 26 comprises a resistor 30 in series with a capacitor 31 which RC series is in turn connected in series with a high frequency parallel tank circuit comprising a coil 32 and capacitor 33. Onthe same side of the tank circuit as the mentioned RC series there is connected a resistor 34 which couples the high frequency component 26 to the output line 25.

The low frequency component of drum 12 likewise includes an RC series made up of resistor 40 and capacitor 41 which RC series connects to one side of a low frequency parallel tank circuit comprising coil 42 and capacitor 43 and to the same side is connected coupling resistor 44 which connects to .the output line 25. A further .input resistor 45 is connected between the drum input line 46 and a grounded line 47 to which one side of both tank circuits is connected.

The inverter-amplifier circuit 11 is coupled to the triggering pulse 16 through a capacitor 50. The inverteramplifier circuit itself includes a resistor 51 connected 'between the DC source 10 and the base 52 of a transistor 61 and Whose output is fed through a coupling resistor to the filter amplifier switch circuit 13. The emitter 56 of transistor 53, capacitor 61, and'the filter amplifier switch circuit 13 are grounded at through respective The filter portion of circuit 13 comprises a parallel arrangement of a coil 90, a resistor 91 and a capacitor 92 connected on one side'to the'DC source 10 and on the other side at a junction 102 through an RC series comprising a capacitor and resistor'101 to the'audio output line 25. An approximate wave shape for junction 102 is shown in FIG. 2. The switch portion of circuit 13 comprises a transistor having its collector 111 connected to junction 102, its emitter112 connected to a 1 volt DC source at 113 audits base to a junction point 114.

Junction point 114 serves as a junction for (a) the low alternating voltage source 21 which is coupled to point 114 through resistor 119 and capacitor 120, (b) the white noise generator. 20 which is coupled to point 114 through capacitor 121, -(c) the output of the integrator circuit 19 which is coupled to point 114 through resistor 70 and for the ungrounded side of the parallel RC arrangement comprised of resistor and capacitor 131 this latter arrangement tending to integrate the DC component and divide the AC component,

Much of the reality of -the snare drum effect achieved by the present invention is believed to reside at least in part in the quality of the white noise produced by the circuitry of the white noise generator 20. Circuit 20 comprises an NPN back biased transistor operative in the zener region and whose base 141 connects to ground at 80 and whose collector 142 is left unconnected. When a semiconductor diode, such as the base-emitter diode of a trancircuit 13 is fed to the audio amplifier 14 where it combines with the output of the drum 12 to produce the desired snare drum eifect.

duced by drum circuit 12 with the other sound sources sistor, is operated with reverse bias large enough to cause zener or avalanche breakdown, the nature of the current flow is random due to the avalanche current multiplication effect. The resulting noise effect is discussed on page 28 in the Silicon, Zener Diode and Rectifier Handbook, published by Motorola, Inc., 5005 E. McDowell St., Phoenix 8, Ariz., 1961 edition. Also see page 123 of the 1961 edition of Semi-Conductor Devices and Applications by R. A. Gainer, published "by McGraw-Hill Book Company, Inc., New York, N.Y. Emitter 143 of transistor 140 corrects to the base of a further transistor 151 through a capacitor 152 and also connects to the collector of transistor 151 through resgistors 153, 154 which are in parallel wtih capacitor 152. The base 150 and collector 155 of transistor 151 are further connected through a resistor 156. The 15 v. source 10 connects at point 157 between resistors 153 and 154 and the White noise output is fed through line 160 to the coupling capacitor 121. The emitter 158 is grounded through resistor 159.

While the wave shape at junction 114 is erratic and difficult to draw, an approximate modulated wave shape 135 is indicated and which is characterized by a 60 cycle envelope 136 and an irregular random frequency 137 beneath the envelope.

While some variation from the following values is allowable it has been found that the circuitry of the invention if designated according to the values listed below will produce a realistic snare drum effect:

Capacitors:

50, mfd .01 61 mfd .047 130 mfd .02 120 mfd .02 92 mfd .015 121 mfd .02 41 mfd .01 43 mfd .04 31 mfd .005 33 mfd .1 100 mfd .02 152 mfd .02

Resistors:

34 220K 153 meg 1 154 lOK 156 meg 1.5 159 ohm 100 Transistors:

Diode 60 Silicon type Coils:

90 henry .5 42 do 32 do 1 In operation, the pulse entering drum 12 splits in drum 12 and starts damped oscillations in both tank circuits and the combined output is fed to amplifier 14. The damped oscillations caused by the energy of pulse 16 on line 46 decay exponentially due to the losses in the tank circuits, thus simulating the decaying sound from a struck drum head. Simultaneously, amplifier 14 is receiving a scrambled noise from the output of circuit 13, which when combined with the drum 12 output produces the desired snare drum effect. Considering this last mentioned noise, operation of the various elements involved will generally be understood by those skilled in the art. It has already been mentioned that circuit 11 inverts and amplifies the triggering pulse 16. In connetcion with this part of the operation a charge is stored in capacitor 61 and a relatively long RC time constant is provided by resistor 70 and capacitor 61. This charge gates the transistor 110. The white noise from generator 20 goes through the gate at junction 114 under a modulating influence asserted by the low alternating voltage obtained from AC source 21.

The filter portion comprising coil 90, resistor 91 and capacitor 92 filters out unwanted noise with resistor 91 acting to change the (Q) of the tank circuit formed by coil and capacitor 92. Contributing to the operation is the parallel RC arrangement previously mentioned and comprised of resistor 131 and capacitor 130 which collectively tend to integrate the DC and divide the AC components of the gated wave.

In summary, the drum 12 furnishes the drum sound of the desired snare-drum sound and the remainder of the circuitry furnishes the snare sound. As to snare circuitry, the inverter amplifier circuit 11, the integrator circuit 19 and the parallel RC circuit of resistor 131 and capacitor 130 all act collectively and basically as wave shaping devices whose overall purpose is to provide a keying voltage at transistor and a desired noise at point 114 for mixing with that produced by white noise generator 20. This white noise and the remaining noise mix at junction 114 under the modulating influence of AC source 21. When transistor 110 is keyed by this mixed and modulated noise input the mixed and modulated noise is amplified and filtered and then passed to amplifier 14 where when it combines with the drum sound produces a realistic snare-drum sound.

Having described the invention, what is claimed is:

1. In an electric organ including a loud speaker, an amplifier for driving the speaker and a triggering pulse source, the combination therewith of a snare drum instrument comprising drum and snare sections connected in parallel between said source and amplifier, said drum section comprising tuned circuits responsive to said source and simulating a drum sound, said snare section comprising a direct current source, an inverter-amplifier-integrator series connected to said source for producing a keying voltage having an exponential form, a white noise generator connected in parallel with said series between said source and a junction point, a substantially low voltage alternating current source connected to said point and being effective to modulate the input to said point, a filteramplifier-switch circuit connected in parallel with said generator betwen said source and point and being responsive to said keying voltage to gate, amplify and filter the noise at said point and having an output simulating a snare sound which when combined with said simulated drum output produces at said speaker a simulated snare drum sound.

2. In an electric organ as claimed in claim 1 in which said white noise generator includes a diode back biased and operative in the zener region as the white noise source.

3. In an electric organ including a loud speaker, an

amplifier for driving the speaker and a triggering pulse,

source, the combination therewith of a snare drum instrument comprising drum and snare sections connected in parallel between said source and amplifier, said drum section comprising parallel connected low frequency and high frequency tank circuits responsive to said source and having a combined output simulating a drum sound, said snare section comprising a direct current source, an inverter-amplifier-integrator series connected to said source for producing a keying voltage having an exponential form, a white noise generator connected in parallel with said series between said source and a junction point, a substantially low voltage alternating current source connected to said point and being effective to modulate the input to said point, a filter-amplifier-switch circuit connected in parallel with said generator between said source and point and being'responsive to said keying voltage to gate, amplify and filter the noise at said point and having an output simulating a snare sound which whencombined with said simulated drum output produces at said speaker a simulated combined snare drum sound.

4. In an electric organ as claimed in claim 3 in which said white noise generator includes a diode back biased and operative in the zener region as the white noise source.

5. In an electric organ including a loud speaker, an amplifier for driving the speaker and a triggering pulse source, the combination therewith of a snare drum instrument comprising drum and snare sections connected in parallel between said source and amplifier, said drum section comprising tuned circuits responsive to said source and having a combined output connected to said amplifier and simulating a drum sound, said snare section comprising a direct current source, pulse shaping means responsive to said source and providing a keying voltage having an exponential form, a White noise generator utilizing a back biased diode operative in the zener region as the white noise source, said generator being connected in parallel with said pulse shaping means between said source and a junuction point, a substantially low voltage alternating current source connected to said point and being efiective to modulate the input to said point, a filter-amplifier-switch circuit connected in parallel with said generator between said source and point and being responsive to said keying voltage to gate, amplify and filter the noise at said point and having an output simulating a snare sound which when connected with said simulate-d drum output produces at said speaker a simulated combined snare drum sound.

6. An electric circuit comprising circuit means for producing clamped oscillations productive of a drum sound, noise means for producing a signal of a decaying wave form productive of a snare sound, and an output circuit, wherein the output of said circuit means is coupled to the output of said noise means in said output circuit in order to produce an output signal which simulates a snare drum sound.

7. An electric circuit comprising circuit means for producing damped oscillations productive of a drum sound, a signal source connected to said circuit means, noise means productive of a snare drum, actuating means connected to said noise means, and an output circuit wherein the output signals of the circuit means and noise means are mixed in order to produce an output signal which simulates a snare drum sound.

8. An electric circuit comprising a signal source, a plurality of parallel L-C circuits coupled and responsive to said signal source for producing an output signal of damped oscillations productive of a drum sound, a noise means, an actuating means coupled to said noise means for producing a noise output signal productive of a snare sound consisting of a decaying wave envelope and an output circuit, wherein output signals of the tuned circuit and noise means are combined in order to produce an output signal which simulates a snare drum sound.

9. An electric circuit comprising a signal source, a plurality of parallel tuned circuits responsive to said signal source to produce an output signal of damped oscillations productive of a drum sound, a noise generator connected with said tuned circuits, gating means coupled to said noise generator and responsive to said signal source to produce an output signal of noise productive of a snare sound and consisting of a decaying wave envelope, an output circuit wherein the two said output signals are combined to produce a sound simulating a snare drum.

10. An electric circuit comprising a plurality of parallel tuned circuits, a noise generator connected to said tuned circuits, a signal source for actuating said tuned circuits to produce an output signal of damped oscillations productive of a drum sound, a gating circuit means connectcd to said noise generator in order to produce an output of signal productive of a snare sound and having a wave envelope which is decaying, an output circuit wherein the output signals of the noise generator and the tuned circuits are combined, said output circuit comprising an amplifier and speaker, so as to reproduce a simulated snare drum sound.

References Cited UNITED STATES PATENTS 3,038,364 6/1962 Bergman 84-103 3,140,336 7/1964 Campbell 841.03 3,141,919 7/1964- Mabuchi 841.26 3,247,308 4/1966 Peterson 84-124 ARTHUR GAUSS, Primary Examiner. 

1. IN AN ELECTRIC ORGAN INCLUDING A LOUD SPEAKER, AN AMPLIFIER FOR DRIVING THE SPEAKER AND A TRIGGERING PULSE SOURCE, THE COMBINATION THEREWITH OF A SNARE DRUM INSTRUMENT COMPRISING DRUM AND SNARE SECTIONS CONNECTED IN PARALLEL BETWEEN SAID SOURCE AND AMPLIFIER, SAID DRUM SECTION COMPRISING TUNED CIRCUITS RESPONSIVE TO SAID SOURCE AND SIMULATING A DRUM SOUND, SAID SNARE SECTION COMPRISING A DIRECT CURRENT SOURCE, AN INVERTER-AMPLIFIER-INTEGRATOR SERIES CONNECTED TO SAID SOURCE FOR PRODUCING A KEYING VOLTAGE HAVING AN EXPONENTIAL FORM, A WHITE NOSE GENERATOR CONNECTED IN PARALLEL WITH SAID SERIES BETWEEN SAID SOURCE AND A JUNCTION POINT, A SUBSTANTIALLY LOW VOLTAGE ALTERNATING CURRENT SOURCE CONNECTED TO SAID POINT AND BEING EFFECTIVE TO MODULATE THE INPUT TO SAID POINT, A FILTERAMPLIFIER-SWITCH CIRCUIT CONNECTED IN PARALLEL WITH SAID GENERATOR BETWEEN SAID SOURCE AND POINT AND BEING RESPONSIVE TO SAID KEYING VOLTAGE TO GATE, AMPLIFY AND FILTER THE NOISE AT SAID POINT AND HAVING AN OUTPUT SIMULATING DRUM SOUND WHICH WHEN COMBINED WITH SAID SIMULATED DRUM OUTPUT PRODUCES AT SAID SPEAKER A SIMULATED SNARE DRUM SOUND. 